It is well known in the food packaging art to stuff thermoplastic bags with various meat products. These products are typically processed and introduced in the form of an emullsion or comminuted form. It is also common practice to introduce liquid smoke, colorant, or other similar additives to certain processed meat products such as sausage or luncheon meats to impart the desired flavor or color to the food product. These additives are usually blended into the food product before the stuffing operation, or impregnated into the bag material itself if the composition of the bag material permits impregnation of such additives. These general practices require an additional step, either during comminutation of the meat or manufacture of the plastic material for the bag, prior to the operation of stuffing the meat into the bag. In the instance of pre-blending the colorant or liquid smoke into the food product, sometimes more additive is used than is really required. For example, if only the surface of the food product requires the colorant or liquid smoke, pre-blending uses excess additive which is blended throughout the food product. Additionally, in the instance of some synthetic thermoplastic materials used in manufacturing the bags, liquid smoke and colorant are not easily added to the polymeric resin itself during the extrusion of this resin into plastic sheet for the bag, and if added are not readily retained by the bag material.
For these reasons, it is desirable to provide a method and apparatus for coating the interior of a bag, which does not require the pre-blending of the additive before the stuffing operation, or the impregnation of the bag material itself with the additive.
Many apparatus for the vacuum stuffing or packaging of meat into a bag are well known. One is the Belam vacuum meat press marketed by Belam, Inc., Oakbrook, Ill. Many patents disclose such vacuum stuffing and/or packaging apparatuses, for example U.S. Pat. Nos. 3,563,764, 3,703,064, 3,760,556, 3,853,999, 3,928,938, 3,950,919, 4,132,048, 4,251,976, 4,586,320, 4,672,793, 3,673,041, and 3,740,921, and U.K. Published Patent Specification No. 1,516,498. Some of these are specific to how to close the bag. U.S. Pat. No. 3,673,041 shows the bag closure means of a vacuum packaging apparatus wherein the bag closure is accomplished by heat sealing with a heat seal bar. U.S. Pat. No. 3,740,921 shows the bag closure means of a vacuum packaging apparatus wherein the bag closure is accomplished by clipping the bag neck with a clipper. U.S. Pat. No. 4,586,320, describes the Furukawa 8150 vacuum meat stuffing apparatus. In particular one of these patents, namely U.S. Pat. No. 3,673,041, is directed to a special heat seal bar for squeezing contaminants such as fatty substances out of the sealing area before the bag panels are fused together to close the bag open neck, and in those instances where solid particulate contaminants are found in the sealing area of the bag neck utilizing steam flushing to clean the inside surfaces of the bag neck area prior to sealing. The disclosures of all of these patents are incorporated herein by reference.
U.S. Pat. No. 4,721,623 (Coffey and Suess, assignors to Oscar Mayer Foods) involves atomized spraying of an aqueous solution of caramel coloring in a humid environment about the surface of a meat product. U.S. Pat. No. 4,958,412 (Stanek, assignor to Grace) involves a sleeve on a stuffing horn wherein the sleeve has grooves for transmitting a liquid additive onto the interior of the plastic. U.S. Pat. No. 4,949,430 (Stanek, assignor to Grace) involves a sleeve on a stuffing horn wherein the sleeve has atomizers for transferring a liquid additive onto the interior of a food-product thermoplastic container. The disclosures of these three patents are also incorporated hereinby reference.
The package of meat can be frozen or refrigerated for storage. Either before or after storage, the package can be subjected to cook-in. Cook-in is a long slow process, typically about 1 to 4 hours, and can be up to 12 hours, at a temperature typically of about 160.degree. F. (71.degree. C.) to 200.degree. F. (93.degree. C.) and can be from about 131.degree. F. (55.degree. C.) to 212.degree. F. (100.degree. C.). Cook-in films are described in U.S. Pat. Nos. 4,411,919, 4,606,922, 4,469,742, 4,855,183, and 4,879,124. In particular, when the meat is turkey, for certain cook-in applications, the bags are perforated, and this is shown in the last-mentioned patent, namely U.S. Pat. No. 4,879,124. An apparatus for making the perforations is described in U.S. Pat. No. 3,038,198. The disclosures of all of these patents are also incorporated herein by reference.